The technique disclosed herein relates to a semiconductor device.
Patent Document 1 (Japanese Unexamined Patent Publication No. 2010-107628) discloses an MEMS mirror. The MEMS mirror includes a mirror, a spring, a movable comb electrode, a fixed comb electrode, etc., and is formed of a substrate with a plurality of silicon layers.
In the MEMS mirror, the mirror is driven by electrostatic force generated between the movable comb electrode and the fixed comb electrode. In order to increase drive force, a larger total area where the movable comb electrode and the fixed comb electrode face each other has been required for the MEMS mirror of this type. In order to increase the total area where the movable comb electrode and the fixed comb electrode face each other, the area of each of the movable comb electrode and the fixed comb electrode may be increased, or the number of the movable comb electrode and the fixed comb electrode may be increased, for example. However, there are various limitations on an increase in the size or number of the movable comb electrode and the fixed comb electrode, and therefore, the size or number of the movable comb electrode and the fixed comb electrode cannot be easily increased.
Some semiconductor devices are each configured such that a movable comb electrode and a fixed comb electrode are used as detection electrodes configured to detect the amount of movement of a moving member. Specifically, the amount of movement of the moving member is detected based on a change in the electrostatic capacitance between the movable comb electrode and the fixed comb electrode. In this case, in order to enhance the accuracy in detection of the amount of movement, the area of each of the movable comb electrode and the fixed comb electrode may be increased, or the number of the movable comb electrode and the fixed comb electrode may be increased, for example. However, there are, as described above, various limitations on an increase in the size or number of the movable comb electrode and the fixed comb electrode, and therefore, the size or number of the movable comb electrode and the fixed comb electrode cannot be easily increased.